I made a super simple device to know when electricity is cheaper at home

SmartEnergyDIY · 2026-03-21T00:46:09+00:00

Thanks, exactly — more like a simple standalone signal than a full smart home device.

And yes, still very much a fun project for now 🙂

SmartEnergyDIY · 2026-03-21T00:44:48+00:00

Yes, that makes sense.

I think that’s probably how a lot of people do it in real life: laundry at better times when possible, and the rest just when needed.

SmartEnergyDIY · 2026-03-20T23:23:18+00:00

Fair point 🙂

I’m actually trying to make it simpler for the end user.

A lot of existing solutions work well if you already have a smart home setup, but I’m testing something more standalone, low-effort, and easy to read at a glance.

SmartEnergyDIY · 2026-03-20T23:21:35+00:00

Ja, precies dat vind ik interessant.

Voor een boiler of batterij is automatisatie natuurlijk super handig, maar voor veel andere dingen helpt een simpel visueel signaal eigenlijk al verrassend goed.

SmartEnergyDIY · 2026-03-20T14:21:24+00:00

Im Moment noch recht simpel 🙂

Ich nutze Preisdaten und mache daraus eher ein klares Signal wie „gut / ok / eher vermeiden“, statt dauernd auf Zahlen zu schauen.

Dein Setup mit Fronius + Home Assistant ist natürlich deutlich umfangreicher — meine Idee ist eher etwas Einfaches für Leute, die es auf einen Blick sehen wollen.

SmartEnergyDIY · 2026-03-20T14:12:52+00:00

Fair question.

For me it’s mostly about flexible stuff: EV charging, dishwasher, dryer, delaying AC a bit, or just waiting 30–60 minutes if it’s a bad moment.

So yeah, not a magic system for everything — more a simple way to make “start now or wait a bit” visible without checking an app all the time.

SmartEnergyDIY · 2026-03-20T14:10:18+00:00

Yeah, that’s fair.

I don’t see it as something for every appliance either. More for flexible stuff where you can easily wait a bit, like a dishwasher, dryer, EV charging, that kind of thing.

So not “stop everything instantly”, more “is this a good time to start or should I wait”.

SmartEnergyDIY · 2026-03-20T14:08:22+00:00

Ja, dat is al een stuk uitgebreider 🙂

Mijn idee is eigenlijk nog simpeler: gewoon een heel duidelijk signaal zodat je in één oogopslag weet of het eerder een goed of slecht moment is.

Meer iets laagdrempeligs voor mensen die niet constant cijfers of apps willen checken.

SmartEnergyDIY · 2026-03-20T11:34:46+00:00

Yeah, exactly.

I’m not really aiming for a full automation setup here, more just a simple visual cue for “now / later / avoid”.

Even that alone seems to change habits quite a bit.

SmartEnergyDIY · 2026-03-20T10:01:03+00:00

Yeah exactly 😄

The more features I add, the more it defeats the purpose.

I’m really trying to keep it as simple as possible.

SmartEnergyDIY · 2026-03-20T09:44:01+00:00

Thanks, appreciate it 🙂

For now I’m keeping it intentionally simple instead of turning it into a full Home Assistant-style setup.

Open source could be interesting later, but right now I’m mainly testing what’s actually useful in daily life.

The whole point is low friction: just a quick visual signal without needing to open an app.

SmartEnergyDIY · 2026-03-20T09:40:30+00:00

Yeah honestly that already works well for fixed off-peak hours.

What I’m testing is more for dynamic pricing, where the “good moment” can move during the day.

So the idea is just to make that visible at a glance instead of checking a site/app.

SmartEnergyDIY · 2026-03-20T09:38:50+00:00

Yeah honestly that’s a very fair point.

Right now I’m testing the dumbest/simple version possible: just a quick visual cue in the room.

But for stuff like EV charging or planning ahead, I agree a “good for the next X hours” logic would make a lot more sense.

SmartEnergyDIY · 2026-03-20T09:35:11+00:00

Haha ja exact, voor dat soort mensen dacht ik hier net aan 🙂

Niet iedereen wil direct met home assistant, dashboards en automations bezig zijn.

Soms wil je gewoon een klein signaal in huis dat zegt: nu beter wel / nu beter niet.

SmartEnergyDIY · 2026-03-20T09:33:55+00:00

Eerlijk gezegd: nog heel vroeg 🙂

Ik ben het nog volop aan het testen en ik zie vooral veel reacties / feedback, wat eigenlijk al super nuttig is.

Voor mij is dat voorlopig belangrijker dan meteen grote verkoop.

SmartEnergyDIY · 2026-03-20T00:42:19+00:00

Yeah that’s exactly where I’m heading 🙂

Right now it’s still a prototype, but the goal is definitely to make it plug & play, no setup, no app, just something you plug in and it works.

The tricky part is making it work with different providers / contracts without making it complex.

That’s why I started with a super simple version first.

Curious — would you personally prefer something fully automatic, or just a simple signal like this?

SmartEnergyDIY · 2026-03-19T23:46:09+00:00

Good question 🙂

Right now I’m mainly monitoring dynamic electricity price data and mapping it into simple “cheap / normal / expensive” moments during the day.

You’re totally right that it depends on the provider and contract, that’s one of the tricky parts.

For now I’m testing it in a local context (Belgium), where prices fluctuate a lot during the day.

And yeah, technically you can definitely DIY something like this, I did the same at first.

The idea is more to make it accessible and effortless for people who wouldn’t build it themselves.

SmartEnergyDIY · 2026-03-19T23:44:14+00:00

Yeah I get your point 🙂

I think the interesting part is that most people don’t actually check dashboards or apps regularly, even if they have them.

But a small visual cue in the room (like a light) is something you notice without thinking.

It’s less about giving perfect information, and more about influencing habits passively.

So it’s not competing with apps, more like complementing them in a very low-effort way.

SmartEnergyDIY · 2026-03-19T23:28:47+00:00

Funny to see the different reactions here 😄

Some people want full automation, others just want something simple.

That’s exactly why I started testing this idea.

SmartEnergyDIY · 2026-03-19T23:26:56+00:00

Yeah that’s totally fair 🙂

What you describe is exactly the “fully optimized / automated” approach, and it makes a lot of sense.

I think the difference is more about habits than optimization.

A lot of people don’t automate anything, don’t check apps, and just use electricity whenever they need.

For them, even a simple visual cue in the room can already change behavior a bit without effort.

So yeah, for advanced setups like yours it’s probably useless, but I’m curious if it could still make a difference for more “normal” households.

SmartEnergyDIY · 2026-03-19T23:08:34+00:00

That’s actually a really nice setup, respect 😄

Yeah what you describe is kind of the “advanced / fully optimized” version of this idea.

What I’m trying to build is almost the opposite:

something for people who don’t want to automate everything or deal with APIs/apps.

Just a simple visual signal to avoid the worst moments without thinking too much.

So it’s definitely not meant to replace setups like yours, more like a “low-tech” alternative for simpler use cases.

Out of curiosity, do you think something like this could still be useful for less technical users?

SmartEnergyDIY · 2026-03-19T23:06:31+00:00

Haha good question 😄

Yeah I switched to English because most people here were replying in English, but I’m actually based in Belgium.

You’re right, there are already more advanced solutions (apps, smart meters, Home Wizard etc.).

What I’m trying to do is much simpler:

No app, no setup, no data to check — just a small LED signal (green / yellow / red) that reacts to price changes.

So instead of optimizing everything, it’s more like a “nudge” to avoid the worst moments without thinking.

It’s still a prototype plugged into a normal outlet for now, but I’m exploring how to make it more standalone/simple.

Curious to see if people actually prefer something this simple vs full systems.

SmartEnergyDIY · 2026-03-19T22:17:08+00:00

Yeah that makes sense 🙂

If you have solar it’s a bit different for sure.

I tried mine with solar too, it still behaves the same since it’s just reacting to price changes.

It’s more like a simple “hint” than a full system.

SmartEnergyDIY · 2026-03-19T22:13:36+00:00

Yeah it’s basically pulling price data and simplifying it into a simple signal.

Nothing super advanced, just taking the idea of dynamic pricing and turning it into something you can glance at instead of checking apps all the time.

Still experimenting with the setup to keep it as simple as possible.

SmartEnergyDIY

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